Hetch Hetchy, a lesser known twin to Yosemite Valley, is home to spectacular scenery and is the starting point for many less-used wilderness trails. The Hetch Hetchy Reservoir is the source of drinking water for much of the San Francisco Bay Area. Although the road to Hetch Hetchy is open year-round during daylight hours (approximately), it may close periodically due to snow in winter and spring. You can take a virtual tour of Hetch Hetchy, courtesy of the San Francisco Public Utilities Commission.